Phantom-circuit loading.



J. F. BALDWIN, JR. PHANTOM CIRCUIT LOADING. APPLICATION FILED mm 21, ms.

1,210,884. at nted an- 2,1917.

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JOHN FRANKLIN BALDUIN, 3B,, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO WEST ERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A GORPORATION on NEW Yonir.

EHANTOM-GIBCUIT LOADING.

Specification of Letters Patent.

Patented Jan. 2, 1917.

Application filed June 27, 1916. Serial No. 106,119.

To all whom 2'25 may concern:

Be it known that l. Jonn FRANKLIN BALDwiN, Jr., a citizen oi the United States, residing at EastOrange, in the county of Essex and State of New Jersey, have invented certain new and useful Improve ments in PhantonnCirc'uit Loading, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone load ing systems, and more particularly to a means for simultaneously loading two physical. circuits and their derived or phantom circuit.

In an arrangement described and claimed in an application filed in the name of J. B. S )eed Serial No. 88,072 filed March 31 .l a 1 ltlo, and assigned to the same assi'gnee as the present application, the simultaneous loading of two physical circuits and their derived phantom circuit is provided or by means 05 a unitary structure comprising two' toroidal. core u'iembers intersecting atright angles on a i'ro'minon diameter. In this structuro the two line windings individual to one oi the physical circuits are located on opposite halves of one toroid, while the line windings iiulividual to the other physical circuit are located on opposite halves of the other tcrcid. Each physical circuit is thus loaded independently ct, and without interference wit", th other physical circuit. Furthermore, when phantom circuit currents flow through the "windings, the distribution of tux is such as to load the phantom circuit as well.

it is an inherent characteristic of a loading coil of the kind just described that, the phantom circuit inductance is only 50% of the physical circuit inductance. This is due to the fact that in phantom circuit operation an improvement upon the invention covered by the application hereinbefore mentioned,

therein, while adding to. the inductive eil'ect of the main windings when phantom circuit currents flow therein. A specific manner in which this may be accomplished is illustrated in the accompanying drawings, in which Figure 1 represents a loading unit, having the winding arrangement of this invention,

arranged for simultaneously loading two physical circuits and their derived phantom circuit; and Fig. 2 illustrates diagrammatically the connection of windings employed.

Referring to Fig". 1, AA represents one physical circuit, BB represents another physical circuit and CC represents a phantom circuit derived from said physical circuits in the well-known manner. As herein illustrated, the loading unit has four semitoroidal magnetic core sections, 1, 2, 3 and 4,

joined together in such a manner as to form in effect two complete toroids intersecting at right angles on a common diameter. The two toroids may be of any suitable magnetic material. For example, they may cona'eniently be formed of finely divided iron,

the individual particles of which are insulated from one another, the core structure being molded by high pressure into the required form, in the manner described and claimed in an application for patent in the name of J. B. Speed, Serial No. 89,409, filed April. 6, 1916, assigned to the same assignee as the present application.

, Core section 1 has located upon it a main winding 56 and an auxiliary or supplementary winding 78. Similarly there is located on core section 2 a main winding 9 40, and an auxiliary winding l112; core section 3 has located upon it a main Winding 1314, and an auxiliary winding BEST AVAILABLE COP lfi l i, and core section i has located on it a main winding 1'T1S and an auxiliary winding 19-20.

As will be seen from an inspection of the drawing, the auxiliary winding of each core section is connected in series with the main winding of the opposite core section; fur thermore. it will be seen that when physical circuit currents are flowing, for example in circuit A. in the direction indicated by the solid arrows, the effects of the main winding 56 on core section 1 and of the main winding 9-10 on core section 2 are additive to produce a flux in the toroid 1-2 in a clockwise direction. as indicated by the large solid arrows. The effects of auxiliary windings 7--8 of core section 1 and auxiliary windings 11-1'2 of core section 2. are also additive but tend to produce a flux in the toroid l'2 in a counter-clockwise direction as indicated by the small solid arrows, thus to a predetermined extent opposing the action of the main windings and counteracting, to the desired extent. their inductive ell'ect. A similar effect will be produced by the main and auxiliary windings of core sections and l by physical circuit currents flowing in the circuit BB. \Vhcn, however, phantom circuit currents flow through the four main windings and four auxiliary windings of the loading unit in the direction indicated by the dotted arrows, it will be seen. that in each branch of the magnetic circuit the auxiliary winding acts to produce a flux in the same direction as that produced by the main winding on that se tion. as indicated by the small and large dotted arrows respectively. It will at once be apparent that the employment of auxiliary windings as herein shown provides ameans of controlling the ration of phantom circuit inductance to physical circuit inductance, and that by a proper selection of the. number of turns to be employed in the auxiliary windings, any desired ratio of phantom circuit inductance to side circuit inductance is obtaincd.

\Vhilc in the embmliment of the invention herein described and shown the auxiliary windin s are arranged to add to the inductive cflect of the main windings when said windings are traversed by the phantom current, and to detract from the inductive efl'ect of the main windings when said windings arctraverscd by the physical circuit current, it will be obvious that said auxiliary windings may be arranged to have the reverse cft'cct. it desired. it will also be. understood that while in the drawing a core structure is shown in which tliextore members are round cross-section, thcy'may, if desired, have iln-r cross-sectional forms. The term "to roid, used herein, is intended to refer to a ring of any desired cross-section. It will also be understood that instead of rings,

rectangular or other forms of lran'ics might e employed, and that, for want of some broader expression. the term toroid is used to denote all such structures.

What is claimed is:

1. An inductance coil comprising two toroidal core members intersecting at right angles on a common diameter, main windings on each of the semi-toroidal core sections thereby formed, .and a supplementary winding on each of said sections, the supplementary winding of one section being in serf i with the main winding of the opposite section.

2. An inductance coil comprising two toroidal core members intersecting at right angles on a common diameter, a main winding on each of the semi-toroidal core sections thereby formed, and a supplementary winding on each of said sections, said supplementary windings being so connected as to add to the inductive effect of the main windings of the two sections lying in the same plane when said windings are connected in parallel, and to detract from said inductiy'e' effect when such windings are connected iii series.

3. An inductance coil com )rising two toroidal core members intersecting at right angles on a common diameter, a main winding on each of the semi-toroidal core 'sections thereby formed, and a su 'iplementary winding on each of said sections, said supplementary windings being so connected as to modify in one way the inductit'e effect of the main windings of the two sections lying in the same plane when said windings are connected in parallel. and to modify in the opposite way said inductive effect when such windings are. connected in'scrics.

-l. .\n inductance coil having two toroidal core members intersecting at right angles on a common diameter. a main winding on each of the semi-toroidal core sections there by ormed, and a supplementary winding on each of said sections, the supplementary winding of each section being connected in series with the main winding of the opposite section in such a manner as to add to the inductive effect of the main windings of opposite sections when said main windings are connected in parallel, and to detract from said inductive effect when said main windings are connected in series.

.3. .\n inductance coil having two toroidal core members intersecting at right angles on a common diameter, a main winding on each of the semi-toroidal co're sections thereby l'ormcd, and a sumilcmenta ry winding on each of said sections, thcsllpplenientary winding of each section being connected in series with the main winding of the opposites-ection in such a manne' as to modify in one way the. inductive effect of the main windings ol opposite sections when said main windings are connected in parallel, and

to modify in the opposite way said inductive effect when said main windings are connected in series.

6. The combination of four line conductors forming two physical circuits and a phantom circuit, and an inductance coil comprising two toroidal core members intersecting at right angles on a common diameter, main windings on each of the semitoroidal core sections thereby formed, one of said niainnvindings being in series with each of said line conductors, and a supplementary w nding oneach of said sections, said supplementary windings being so connected with respect to said main windings In witness whereof, I hereunto subscribe my name this 26th day of June, A. D. 1915.

JOHN FRANKLIN BALDWIN, JR. 

